Kernel: Make (f)statvfs report filesystem ID correctly

Author: https://github.com/BenWiederhake
Commit: ad5061bb7a
Pull-request: https://github.com/SerenityOS/serenity/pull/10831

Kernel/Syscalls/statvfs.cpp

@@ -26,7 +26,7 @@ ErrorOr<FlatPtr> Process::do_statvfs(FileSystem const& fs, Custody const* custod
     kernelbuf.f_ffree = fs.free_inode_count();
     kernelbuf.f_favail = fs.free_inode_count(); // FIXME: same as f_bavail
 
-    kernelbuf.f_fsid = 0; // FIXME: Implement "Filesystem ID" into Filesystem
+    kernelbuf.f_fsid = fs.fsid();
 
     kernelbuf.f_namemax = 255;